Nash’s VReversal is completely strike invincible but not projectile invincible. In order to properly punish Nash’s VReversal, you need a projectile-type move that can reach him as his character model reappears from his VReversal. Luckily, Ibuki has a multitude of moves that can punish Nash’s VReversal.
If you have no resources (VTrigger/CA), you can punish Nash’s VReversal with a fully-charged VSkill. You have to wait for Nash to pass Ibuki’s body before charging it or else she does not turn around to punish it.